Cryolite
Na2NaAlF6IMA symbol: Crlgrandfathered
Cryolite is a halide mineral with the formula Na2NaAlF6, crystallizing in the monoclinic system. It has a Mohs hardness of 2-5, typically colorless, white, black or brown in color, with a greasy or pearly luster, a specific gravity of 2.972. Its streak is white.
Photos
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Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | P 1 21/n 1 |
| Cell (Å, °) | a = 5.4139, b = 5.6012, c = 7.7769; α = 90, β = 90.183, γ = 90 |
| Cell volume | 235.828 ų, Z = 2 |
| Axial ratios | 0.9666:1:1.3884calculated from COD 9006157 |
| Source structure | COD 9006157 (Physics and Chemistry of Minerals, 1993) — 1 of 20 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 1.946 | 2.754 | 2.748 | 1.944 | 1.573 | 3.893 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 70.1 | 63.1 | 55.1 | 47 | 41.3 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9006157; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 2.957 g/cm³calculated from COD 9006157 |
|---|---|
| Hardness (Mohs) | 2-5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 2.972 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, brown, colorless, red, whitesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) |
| Luster | greasy, pearly, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 209.94 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Na 32.85%, Al 12.85%, F 54.3% |
Classification
| Nickel-Strunz (10th) | 3.CB.15Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 3.CB.15Wikidata (CC0) |